A few notes on how I see things, and you're welcome to disagree, I'm mostly trying to explain how I run things.
Ships (not on Silent Running), planets and the like are trivially detectable, atleast if they are on the same side of the star as you. You don't get a lot of information, just stuff like "Ship, probably a big one" or "Gas Giant".
These are detected without roll at some distance.
Object can "hide". The moons of a gas giant are much easier to count when you're close, and a ship can be lost easily enough if there's interference, ie it's stationary over the pole of a planet.
In general, ships aren't detected until you're "reasonably close" - which might still mean a day away.
Most imperial ships will indentify themselves by vox at significant distance, but not always.
Active Augury will tell you about ships on Silent Running in the affected volume.
It also tells you what class of ship it is, assuming you have the ability to identify it.
Loki Q-ships will usually identify as another type of transport, for example.
Active Augury also tells you about "non-emitting objects" ie small astroids.
Focused Augury tells you about this one specific ship you're scanning. types and locations of components. Are shields active (yes they are!), are weapons powered etc. The scanned ship will know it is being scanned, some may consider this a hostile action.
Focused Augury can still be fooled via eg. Wolf in Sheep's Clothing.
Edited by Tenebrae, 04 May 2014 - 03:31 PM.